Ancient disk controllers - test-drb@ccmp.vtda.org

18 Apr 1999

see below, please.

Dick

-----Original Message-----
From: Ethan Dicks &lt;ethan_dicks(a)yahoo.com&gt;
To: Discussion re-collecting of classic computers &lt;classiccmp(a)u.washington.edu&gt;
Date: Saturday, April 17, 1999 8:17 PM
Subject: Re: Ancient disk controllers

...

--- Tony Duell &lt;ard(a)p850ug1.demon.co.uk&gt; wrote:

   The final
connector, J6 is 50 pins.
   Which pins are used on the 50 pin connector? Could it be pinned out as a 
 SCSI port. Or is it possibly some custom host interface? 
It could be a custom host interface.  Among other anomalies, I don't see
any terminating resistors.

  For example I 
 have here the data sheet for the WD1001 controller. It uses essentially 
 the chipset you mentioned. It has a 50 pin host connector, but it sure 
 ain't SCSI. 
Can you scan that data sheet or send me a photocopy?  I'd pay for
copying/mailing.

  20MHz/4 = 5MHz = standard ST506 data rate. 

Right.  It's the right rate for an 8" disk. 

Nope, it's not!  the right rate for 8" Winchesters is 4.34 MHz!

...
 > 8MHz is a common enough clock for the 8x300 series
of CPUs as well. 

That's true enough.

...
 OK.

  What bothers me, if this _is_ a SCSI controller
is that there seems to be 
 no way of setting the device address.  
No place that I can see.

> My guess is that it's a sort-of WD1001 clone. 

It predated the WD1001 by some time.

...
 OK.  That makes sense.  In fact, when I read the recent
debates of
WD1001's, I thought of this board.  I didn't think I could find it
as fast as I did.  It could have been packed a lot deeper than it
was.

Thanks for the insights.

-ethan

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